Question: WEIGHT LOSS FROM DIET

When 40 people used the Weight Watchers diet for one year, their weight losses had a standard deviation of 4.9lb (based on data from “Comparison of the Atkins, Ornish, Weight Watchers, and Zone Diets for Weight Loss and Heart Disease Reduction,” by Dansinger, et al., Journal of the American Medical Association, Vol. 293, No.1). Use a 0.01 significance level to test the claim that the amounts of weight loss have a standard deviation equal to 6.0 lb, which appears to be the standard deviation for the amounts of weight loss with the Zone diet.